mike@yenta.alb.nm.us (Mike Werner) (12/27/90)
Howdy Netland, What I'm trying to find out is a wee bit of information on the construction and operation of Vacuum Tubes. More specifically I want to understand what all of the pins are or can be in a tube amplifier. If anyone knows of a good book that might give me all the answers that would be appreciated also. I know a little about the field and heater pins but it's very little and that's where my psudo-expertise ends. Multithanks in advance, -Mike- -- "There are three marks of a superior man: being virtuous, he is free from anxiety; being wise, he is free from perplexity; being brave, he is free from fear."
mcovingt@athena.cs.uga.edu (Michael A. Covington) (12/28/90)
OK, here are some tube basics. Tubes act like FETs, with cathode=source, control grid=gate, and plate (anode) = drain. That means that with a triode tube, you have those three pins, plus two pins for the heater. Two additional grids are sometimes used. In a pentode tube the additional grids are called the screen grid (usually connected to a constant positive voltage close to that of the plate supply) and the suppressor grid (grounded). These introduce shielding between the control grid and the plate. Because the plate is so large, the capacitance from control grid to plate would be large if there were no shielding in there. Also, a pentode has a characteristic curve like a FET, i.e., it is basically a current source controlled by voltage. A triode's characteristic curve consists of slanting rather than horizontal lines, like an FET at low voltage. Of course many popular tubes have more than one tube in the same envelope. For instance the 12AX7 is two triodes. .
kludge@grissom.larc.nasa.gov ( Scott Dorsey) (12/29/90)
In article <1990Dec27.020813.4864@yenta.alb.nm.us> mike@yenta.alb.nm.us (Mike Werner) writes: >Howdy Netland, > > What I'm trying to find out is a wee bit of information on the > construction and operation of Vacuum Tubes. More specifically > I want to understand what all of the pins are or can be in a > tube amplifier. If anyone knows of a good book that might give > me all the answers that would be appreciated also. I know a > little about the field and heater pins but it's very little > and that's where my psudo-expertise ends. Run out and buy yourself a copy of the RCA Tube Manual. Yes, it's still in print, and yes, your local RCA tube dealer (any big electronics distributor) will have a copy. Or you can just think of a triode as being some kind of big hot JFET with weird bias voltages... current goes into the plate and out the cathode, and the amount that flows varies with the voltage on the grid. --scott -- Scott Dorsey/ Kaptain Kludge NASA Langley Research Center, Aircraft Guidance and Control Branch Disclaimer: Neither NASA nor Lockheed really know anything about what
myers@hpfcdj.HP.COM (Bob Myers) (01/03/91)
>Tubes act like FETs, with cathode=source, control grid=gate, and >plate (anode) = drain. That means that with a triode tube, you have >those three pins, plus two pins for the heater. Oh, God, am I starting to feel old. Anybody else remember the books/magazine articles which began, "FETs are like tubes, with the source = cathode...." (And I'm not even all THAT old yet. Sheesh.) Bob Myers KC0EW HP Graphics Tech. Div.| Opinions expressed here are not Ft. Collins, Colorado | those of my employer or any other myers@fc.hp.com | sentient life-form on this planet.
danr@ais.org (Daniel Romanchik) (01/11/91)
In article <17660136@hpfcdj.HP.COM> myers@hpfcdj.HP.COM (Bob Myers) writes: >>Tubes act like FETs, with cathode=source, control grid=gate, and >>plate (anode) = drain. That means that with a triode tube, you have >>those three pins, plus two pins for the heater. > >Oh, God, am I starting to feel old. Anybody else remember the books/magazine >articles which began, "FETs are like tubes, with the source = cathode...." 8-). I had the same reaction, and I'm only 35. Dan KB6NU -- Dan Romanchik (danr@irie.ais.org, danr@m-net.ann-arbor.mi.us, 313-930-6564) "If it ain't broke, don't fix it." -- Ancient Engineering Maxim
mcovingt@athena.cs.uga.edu (Michael A. Covington) (01/11/91)
In article <CKN+#9$@irie.ais.org> danr@ais.org (Daniel Romanchik) writes: >In article <17660136@hpfcdj.HP.COM> myers@hpfcdj.HP.COM (Bob Myers) writes: >>>Tubes act like FETs, with cathode=source, control grid=gate, and >>>plate (anode) = drain. That means that with a triode tube, you have >>>those three pins, plus two pins for the heater. >> >>Oh, God, am I starting to feel old. Anybody else remember the books/magazine >>articles which began, "FETs are like tubes, with the source = cathode...." > > 8-). I had the same reaction, and I'm only 35. I wrote the passage that Bob Myers quoted (i.e., the passage with the maximum number of >>> above), and I do feel old, and I'm only 33.
masaki@elaine13.stanford.edu (Albert Huntington) (01/12/91)
Then again, did you ever notice the vacuum tube you're probably looking at right now? A cathode ray tube is a special purpose vacuum tube, and probably the most widely used. Albert Huntington masaki@portia.stanford.edu
krikori@eniac.seas.upenn.edu (Raffi Krikorian ) (01/24/91)
Does anyone know of a case(s) where someone was injured while using a vacuum tube amplifier?
dam@cs.glasgow.ac.uk (David Morning) (01/24/91)
In article <36147@netnews.upenn.edu> krikori@eniac.seas.upenn.edu (Raffi Krikorian ) writes: > > Does anyone know of a case(s) where someone was injured while using >a vacuum tube amplifier? Yeah! I was injured by a Hiwatt AP100 guitar amp. It fell off the cabinet it was resting on and landed on my foot breaking a toe. Dave
FC138001@ysub.ysu.edu (Phil Munro) (01/25/91)
In article <36147@netnews.upenn.edu>, krikori@eniac.seas.upenn.edu (Raffi Krikorian ) says: > > Does anyone know of a case(s) where someone was injured while using >a vacuum tube amplifier? I burned myself once, but I don't remember ever getting cut with glass or poisoned with chemicals.!!! ????
ken@uswat.uswest.com (Kenny Chaffin) (01/26/91)
In article <91025.101754FC138001@ysub.ysu.edu-> FC138001@ysub.ysu.edu (Phil Munro) writes: ->In article <36147@netnews.upenn.edu>, krikori@eniac.seas.upenn.edu (Raffi ->Krikorian ) says: ->> ->> Does anyone know of a case(s) where someone was injured while using ->>a vacuum tube amplifier? -> -> I burned myself once, but I don't remember ever getting cut with glass ->or poisoned with chemicals.!!! ???? Well--I dropped one on my foot once! Boy are those power transformers heavy! 8-) 8-).. KAC WB0E "Anybody want a drink before the war?" Sinead O'Connor >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Kenny A. Chaffin {...boulder}!uswat!ken U S WEST Advanced Technologies (303) 930-5356 6200 South Quebec Englewood, CO 80111 <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
kitagawa@will.ntt.jp (Masahiro Kitagawa) (01/26/91)
In article <36147@netnews.upenn.edu> krikori@eniac.seas.upenn.edu (Raffi Krikorian ) writes: | Does anyone know of a case(s) where someone was injured while using |a vacuum tube amplifier? ^^^^^^^^^^^^^^^^^^^^^ If high power amplifiers in broadcast or ham radio stations are included, sure enough, there have been many injured and dead, as the plate voltages are ranging from KV to 10 KV. I heard the engineer at the radio station in Saipan Is. was dead about ten years ago by the accident. I had built several high power amplifiers for ham radio and lab experiments in my school days. Fortunately I am still alive. But I will use Power MOS FETs next time as they need only 150 V to make KW. As for audio amplifiers and radio receivers, the plate voltages are usually hundreds volts and not so fatal unless your hands are wet or sweat. Anyway, be careful ! *--- **** ***-- *--* *-* *-* Masahiro Kitagawa NTT Research Labs. Tokyo Japan kitagawa@will.ntt.jp
barry@mothra.rose.hp.com (Barry Fowler) (01/30/91)
Go to your local electronics store and get "The RCA Receiving Tube Manual" (I've still seen them around although RCA no longer makes tubes). Other possible sources of information is to go to your local library and look up the "electronics section". If your library is anything like most I've seen, their electronics is about 20 years behind and will be full of tube "theory of operation". Another idea: Get a copy of the ARRL (American Radio Relay League) handbook dated in the 50's or 60's. There's lots of info. about tubes in them. Have fun, Barry (tubes are "real electronics") Fowler
witt@iccgcc.decnet.ab.com (01/30/91)
In article <36147@netnews.upenn.edu>, krikori@eniac.seas.upenn.edu (Raffi Krikorian ) writes: > Does anyone know of a case(s) where someone was injured while using > a vacuum tube amplifier? Well, I was almost seriously burned because of a tube radio. When I was a kid, I had a real old GE radio on a table next to my bed. It wasn't in a cabinet anymore, just the chassis with all of the tubes exposed. I used to sit up late some nights tuning around on the AM band listening for stations in other states. Well, anyway, one night I fell asleep with the radio on and sometime during the night my pillow fell on top of it. I woke up to the sound of my dog barking and my foam rubber pillow blazing away next me. Luckily I didn't get burned and I was able to toss the pillow out the window. Close call. This incident definitely made me a believer in solid state electronics. Tom